The Department of Defense formally announced Tuesday details of the new Trump policy on transgender troops, saying that personnel must serve in their biological sex and not their preferred gender – although current transgender troops who don’t meet the new standards will be allowed to stay.

The new policy means that no one will be booted from the military, although men and women who sign up for the military after it takes effect won’t receive an exemption. The policy will go into effect in 30 days.

It was written at the directive of President Trump and overturns the Obama-era policy that allowed personnel to serve under their gender identity. A man who identified as a woman, for example, could serve alongside women. In the future, such an arrangement won’t be permitted.

A story on the Department of Defense website says the policy “was developed by military and civilian experts” on combat readiness “who consulted with medical professionals.”

Persons who have sex-reassignment surgery or are diagnosed with gender dysphoria are ineligible for the military under the new policy.

The new policy advances military readiness, the department says.

“To maintain a military force that is worldwide deployable and combat effective, the military must set high standards, and all military members must sacrifice to meet these standards,” a DoD explanation of the policy reads. “In fact, just over 70 percent of prime military-age Americans cannot meet the military's standards.

“... Persons with a history of gender dysphoria – a serious medical condition – and who have undergone certain medical treatment for gender dysphoria, such as cross-sex hormone therapy or sex reassignment surgery, or are unwilling or unable to meet the standards associated with their biological sex, could adversely impact unit readiness and combat effectiveness. For this reason, such persons are presumptively disqualified for service without a waiver.”

The Department of Defense maintains that the new policy is not a “ban.”

“A transgender person is someone who identifies as a gender other than his or her biological sex,” the DoD explanation reads. “For example, a person who is biologically male but identifies as female may identify as transgender. Transgender individuals are not excluded from military service, and DOD policy specifically prohibits discrimination based on gender identity. But all persons, whether or not they are transgender, must meet all military standards, including the standards associated with their biological sex. Waivers or exceptions to these standards may be granted on a case-by-case basis.”

Meanwhile, troops who signed up for the military under the old policy will be allowed to stay: “Service members who joined the military in their preferred gender or were diagnosed with gender dysphoria before the 2018 policy takes effect are exempt from the new policy and may serve in their preferred gender.”